Isolation,Identification And Biocontrol Prospects Of Mycoparasite On Oospores From Scolerospora Graminicola

The downy mildew of millet is an important disease in millet production,which has great influence on the yield and quality of millet.At present,the main control methods are breeding for disease resistance and chemical control.However,the breeding of disease-resistant varieties neeed long time,and chemical agents will have adverse effects on the environment,so a biological control method is urgently needed.In this study,Jingu 21 was taken as the research object.The pathogenicity of the oospores of the albino pathogen of millet from Wuxiang,Qinshui and Taigu was determined,and the mycoparasite were isolated and identified from the oospores from the three regions.The effects of the mycoparasite on the germination and growth of Jingu 21 seeds were studied.Wheat and Corn were selected to determine the safety of mycoparasite.The effects of mycoparasite on the initial infection and reinfection of the downy mildew of millet were preliminarily explored.The main results were as follows:1.The pathogenicity of oospores from Wuxiang,Qinshui and Taigu was tested by the method of oospore soil mulching.It was found that the oospores of Qinshui were the most virulent to Jingu 21.The artificial vernalization at 4 ? could effectively promote the oospores to pass the dormant period.2.A total of 55 strains of mycoparasite were isolated from the oospore of the three regions,which were identified as five species of Fusarium,which are Fusarium proliferatum and Fusarium verticillioides,Fusarium incarnatum,Fusarium equiseti and Fusarium chlamydosporum.3.By studying the effects of different concentrations of 55 strains of mycoparasite on the safety of Jingu 21 and the germination and growth of seeds,it was found that the fermentation stoste could inhibit the germination of seeds,and three strains were pathogenic to seeds;The 50% of the fermentation stoste promotes the growth of millet root length and shoot length.The 10% of the fermentation stoste can increase the germination of seeds and promote the root length and shoot length of the millet.In the 10% of the fermentation stoste,nine representative dominant strains were screened out.4.Using the method of dipping the radicle and the spray inoculation method to study the safety of the mycoparasite on wheat and corn,five strains of WX4-2,QS1-2,QS2-2,TG3-2 and TG5-2 with certainbiocontrol potential were screened out.5.By studying the effects of fermentation stoste of five mycoparasite on the initial infection and reinfection of the downy mildew of millet,screened out two strains of Fusarium chlamydosporum TG5-2and TG3-2,were have high inhibition on the initial infection and reinfection of the downy mildew of millet.